2000 ranger ABS light is on

[Datnip]

The lower bolt that holds the Pads and Caliper to the right front wheel
came loose fell out and got jammed under the rotor. This fractured my rim in six places but did not damage anything else. Even so I have replaced both rotors and pads. I got a replacement bolt from the junk yard off of a ranger they had and made sure both sides are tight so this can't happen again. But for some reason the ABS light is on. I have checked the wires on both sides and everything looks to be just fine. Anyone have any ideas? The ABS light was not on before this. Or does anyone have any idea how to find out what is triggering the ABS light?
Thanx for the help.

[gmtech1]

Did you replace the rotor with the correct one? The ABS sensor ring is attatched to the rotor. If there is no ring for the sensor, will set a speed sensor code.

[Datnip]

The ABS light was on before I replaced rotors. It came on when the bolt came off and fractured the rim. But the ABS ring your talking about is inside the wheel bearing hub. I had to replace the wheel hub a few years back because the ABS was kicking in when I was coming to stop no matter what the road conditions were.
I guess I will have to look things over all over again. This is so weird. Does anyone know if there is a device that would tell me the fault like the OBDII code readers?

[Datnip]

Sorry, Yes I replaced with the correct Rotors. they are an exact copy of the old ones.

[Datnip]

Well I finally got the ABS code from Advanced auto.
B1230 is the code which tells me that the ABS rear speed sensor
needs replacing. Once I get my truck back from front end alignment
and tires I will get one and see what happens.
I hope this helps anyone that might have this same issue.